Shutter for cinematographs



A. VAN WORMER.

SHUTTER FOR CINEMATOGRAPHS.

urucmou HLED Aus.2a. law.

1,342,076. Patented June 1, 1920.

.BY Q ATTORNEY.

ABBA VAN WORKER, OF FORT WAYNE, INDIANA.

SHUTTER FOR CINEMATO GRAPHS.

Specification of Letters Patent.

Patented J u no 1., 1920.

Application filed August 28, 1919. Serial No. 320,437.

To all whom it may concern:

Be it known that I, Anna VAN Womvmn, a citizen of the United States of America, and resident of Fort Wayne, in the county of Allen and State of Indiana, have invented certain new and useful Improvements in Shutters for Cinematographs, of which the following is a specification.

This invention relates to improvements in shutters for cinematographs and the object thereof is to provide a device of its 0 ass with which a reduction in the amount of flickering that generall occurs in projecting films will be accom lis ed.

i The object of t e invention 15 accomplished by the construction illustrated m the accompanying drawings in which:-

Figure 1 is an elevation showing one of a pair of cooperating disks;

Fig. 2 is a similar view of the other 00 operating disk; and

Fig. 3 is a side view of the disks mounted in coiiperative relation and shown in section on a line extending horizontally through the centers of Figs, 1 and 2.

Similar characters of reference indicate correspondin parts throughout the several views and re erring now to the same:

1 and 2 are shutter disks, each having a central spider 3-4 respectively for its support. The hub 5 of the spider 4 is split and has a air of lugs 6 through which a screw 7 exten s so that the hub may be securely clamped upon the operating shaft 8. The hub 5 has an extendin sleeve 9 upon which is adjustably mounte the hub 10 of the spider 3, there being a screw 11 for securing it upon the sleeve in adjusted positions. When thus secured the disks are held in parallel positions and are adjustably spaced apart.

The disk 1 has two exposure openings 12 located opposite each other and a cover blade 13 and also a shadow blade 14 that are located opposite each other and between the exposure openings, The cover blade and shadow blade each have a series of concentric openings 15 with intervening opaque bars 16 between the corresponding concentric openings, the outer ends of each bar of the shadow blade terminating respectively with pointed extensions 17.

The disk 2 has two exposure openings 18 located opposite each other, and a cover blade 19 and also a shadow blade 20 that are located opposite each other and between the exposure openings therein. The cover blade 1 9 and the shadow blade 20 each have a series of concentric openings 21 with intervenng opaque bars 22 between the correspondmg openings, the outer ends of each bar of the shadow blade terminating respectively with pointed extensions 23.

The concentric slots of the blades of the disk 1 have the same radii as the bars of the corresponding blades of the disk 2 so that the bars of the one disk will obstruct the light projected through the slots in the blades of the other disk when the two disks are positioned to turn upon a common axial center, it being the intention to position the disks so that their blades are similarly posed.

In the operation of the invention the shutter is applied in connection with a cinematographic projector (not shown) and rotated in the customary manner so that the light pro ected through the lens of the instrument will pass through the disks unobstructedly during the time of the passages of the exposure openings before the lens andwill become obstructed more or less during the passages of the cover and shadow blades, the intention being to step the film in the instrument from one picture to the succeeding picture during the passage of the cover blades across the path of the projected light from the lens, the shadow blades serving to balance the interruption caused by the cover blades.

By constructing the cover and shadow blades so that the bars of the blades of one disk will obstruct the passage of light from the lens directly through the slots in the blades of the other disk, the picture projected by the light is. obliterated leaving only a diffusion of light projected indirectly through the slots efl'ecting the projection upon the screen of diffused light instead of corresponding periods of complete interruptions of projected light. Thus, in using the present apparatus the contrast between the uninterrupted exposures and the obstructed periods intervenin therebetween is less marked than when t e ordinary device is employed, and especially is the contrast lessened by forming the slots in the blades in concentric arrangement so that the movement of the bars of the blades that obstruct the light is in line with the circular motion of the disks.

More or less diffused light will be pro jected through the blades accordingly as the disks are adjustably positioned farther apart or closer together, and such adjustments are accordingly made to suit the peculia r character of the various films.

The effect of the pointed extensions at the ends of the bars of the shadow blades is that the projected light becomes blended by the partial obstruction of the light afforded by the extensions as they enter and leave the projected rays, thus tending to reduce the harshness of the obstruction effected by the shadow blades so that less flickering is noticeable on the screen.

\Vhat I claim is:-

1. In a cinematographie shutter, a pair of disks supported to rotate upon a common axial center and being adjustably positioned apart from each other, each disk having opposite exposure openings and a cover blade and also a shadow blade oppositely positioned between the exposure openings, the blades of each disk having a series of concentric slots and corresponding intervening concentric bars, the bars in the blades of one disk being positioned so as to obstruct light rojected through the slots of the other isk.

2. In a cinematographic shutter, two disks adjustably spaced apart and arranged to rotate together upon a common axis, each disk having opposite ex sure openings for unobstructed passage 0 li ht therethrou h and having also a cover an ashadow blu e oppositely disposed between the exposure openings and having a series o f alternate slots and bars concentrically disposed, the bars of one disk being located so as to obstruct the direct passage of light through the corresponding slots-in the other disks.

3. In a rinematographic shutter, two disks spaced apart and arranged to rotate upon a common axis,each disk having exposure openings therein and oppositely disposed b ades between the openings, the blades having aseries-of concentric slots and intervening bars, the bars of the blades of one disk being so arranged as to obstruct the light projected through the slots in the blades of the other disk.

4. In a cinematographic shutter, a pair of disks spaced apart and arranged to rotate upon a common axis, each disk having exposure openings therein and oppositely disposed b ades between the openings ,rovided with concentrically arranged liars and corresponding concentric slots interveningly disposed, the ends of the bars of one of the blades of each disk. having pointed extensions, the bars in the blades of one disk being so disposed as to obstruct light projected through the corres onding slots in the blades of the other dis c.

In testimony whereof I ailix my signature in presence of two witnesses.

AREA VAN WORMER. Witnesses-z MA'rxnnA Mn'rrmm, VVAL'rnn G. BURNS. 

